feat(player,queue): loudness strip controls and normalization readout fixes

- Add Tauri command to delete loudness_cache rows for a track and helpers in AnalysisCache.
- Queue tech strip: click dB to reseed loudness; LUFS target picker via body portal; metric styling aligned with strip (no link chrome).
- Player store: reseed clears local cache and replays analysis seed; show loudness dB from SQLite cache when live state is still null; allow first numeric normalization-state update through the short duplicate filter.
- audio_update_replay_gain: resolve loudness from the requested gain when playback URL is not pinned yet.

src-tauri/src/analysis_cache.rs

@@ -83,6 +83,25 @@ impl AnalysisCache {
         Ok(Self { conn: Mutex::new(conn) })
     }
 
+    /// Remove all `loudness_cache` rows for this logical track (bare id and `stream:` variant).
+    pub fn delete_loudness_for_track_id(&self, track_id: &str) -> Result<u64, String> {
+        if track_id.trim().is_empty() {
+            return Ok(0);
+        }
+        let conn = self
+            .conn
+            .lock()
+            .map_err(|_| "analysis_cache lock poisoned".to_string())?;
+        let mut total: u64 = 0;
+        for tid in track_id_cache_variants(track_id) {
+            let n = conn
+                .execute("DELETE FROM loudness_cache WHERE track_id = ?1", params![tid])
+                .map_err(|e| e.to_string())?;
+            total = total.saturating_add(n as u64);
+        }
+        Ok(total)
+    }
+
     pub fn touch_track_status(&self, key: &TrackKey, status: &str) -> Result<(), String> {
         let now = now_unix_ts();
         let conn = self.conn.lock().map_err(|_| "analysis_cache lock poisoned".to_string())?;

src-tauri/src/audio.rs

@@ -4053,9 +4053,13 @@ pub fn audio_update_replay_gain(
     } else {
         None
     };
+    // If `current_playback_url` is not pinned yet, still honour JS `loudness_gain_db`
+    // so `loudness_ui_current_gain_db` can show a number (otherwise `and_then`
+    // drops the requested gain entirely).
     let resolved_loudness_gain_db = url_for_loudness
         .as_deref()
-        .and_then(|u| resolve_loudness_gain_from_cache(&app, u, target_lufs, loudness_gain_db));
+        .and_then(|u| resolve_loudness_gain_from_cache(&app, u, target_lufs, loudness_gain_db))
+        .or(loudness_gain_db);
     let effective_loudness_db = if norm_mode == 2 {
         match url_for_loudness.as_deref() {
             Some(u) => loudness_gain_db_or_startup(&app, u, target_lufs, loudness_gain_db),

src-tauri/src/lib.rs

@@ -1250,6 +1250,14 @@ fn analysis_get_loudness_for_track(
     }}))
 }
 
+#[tauri::command]
+fn analysis_delete_loudness_for_track(
+    track_id: String,
+    cache: tauri::State<'_, analysis_cache::AnalysisCache>,
+) -> Result<u64, String> {
+    cache.delete_loudness_for_track_id(&track_id)
+}
+
 #[tauri::command]
 fn analysis_enqueue_seed_from_url(
     track_id: String,
@@ -4099,6 +4107,7 @@ pub fn run() {
             analysis_get_waveform,
             analysis_get_waveform_for_track,
             analysis_get_loudness_for_track,
+            analysis_delete_loudness_for_track,
             analysis_enqueue_seed_from_url,
             download_track_offline,
             delete_offline_track,